Plasma systems are used to control plasma processes. A plasma system includes multiple radio frequency (RF) sources, an impedance match, and a plasma reactor. A workpiece is placed inside the plasma chamber and plasma is generated within the plasma chamber to process the workpiece.
It is important that the workpiece be processed in a similar or uniform manner. To process the workpiece in a similar or uniform manner, various parameters associated with the plasma reactor are controlled. As an example, it is important to control directionality of ion flux during processing of the workpiece. The control in directionality helps increase an etch rate and achieve a certain aspect ratio of features of the workpiece.
With the processing of the workpiece in the uniform manner, it is important to simultaneously maintain lifetime of various components of the plasma chamber. With an application of RF power to some of the components, the components wear faster and do not last for their lifetime. Moreover, due to such wear, the components adversely affect the directionality of ion flux, which adversely affects the uniformity in processing of the workpiece.
Moreover, current dielectric etch tools have fixed edge hardware. For example, a height of a lower electrode extension of the plasma reactor, or a material of the lower electrode extension, or a gap between an upper electrode and a lower electrode are optimized to process the workpiece at its edges. The fixed edge hardware does not allow flexibility in processing the workpiece at its edges.
It is in this context that embodiments described in the present disclosure arise.